Conventionally a so-called carousel type sputtering apparatus is known which forms a multi-layered thin film on each of a plurality of substrates by sputtering a plurality of targets which are placed opposed to an outer circumferential surface of a polygonal or cylindrical drum type substrate holder, while the drum type substrate holder which holds the substrates onto the outer circumferential surface is being rotated (see Japanese Patent Laid-Open No. 2001-234338, for example).
In a carousel type sputtering apparatus, such as that described in the above patent No. 2001-234338, a plurality of substrates need to be fixed onto an outer circumferential surface of a drum type substrate holder before a film forming process is started, and the plurality of substrates need to be removed from the outer circumferential surface of the drum type substrate holder after the film forming process is completed.
In such a carousel type sputtering apparatus, a pressure in a vacuum chamber often needs to be recovered to an atmospheric level to remove the substrate manually.
It requires a long evacuation time, and since it is not automatically performed, in some cases the productivity cannot be improved.
Thus, another carousel type sputtering apparatus is known which includes a film forming chamber, a spare chamber separated from the film forming chamber by a valve (gate valve), and a drum type substrate holder which is movably installed between the film forming chamber and the spare chamber, so that a plurality of substrates are fixed onto an outer circumferential surface of the drum type substrate holder in the spare chamber, and the drum type substrate holder is moved to the film forming chamber to form a film, and after a film is formed, the drum type substrate holder is moved back to the spare chamber to exchange the substrates (see Japanese Patent Laid-Open No. 2001-185774, for example).
However, the carousel type sputtering apparatus, such as that described in the above patent No. 2001-185774 further includes: moving means to move a drum type substrate holder from a film forming chamber to a spare chamber to exchange substrates; and a spare chamber, and this makes the configuration of the apparatus complicated and larger, which should be improved.
Further, in the carousel type sputtering apparatus, such as that described in the above patent No. 2001-185774, the action to remove a substrate on which a film is formed at an outer circumferential surface of a drum type substrate holder in a spare chamber, and the action to fix a new substrate onto the outer circumferential surface of the drum type substrate holder are generally performed manually under atmospheric pressure, which should be improved in terms of working efficiency.
The present invention is accomplished in view of the above problems, and it is an object of the present invention to provide a thin film forming apparatus in which the action to fix a substrate onto an outer circumferential surface of a drum type substrate holder and the action to remove the substrate from the outer circumferential surface of the drum type substrate holder are performed through a simple arrangement, and also under vacuum with high efficiency.